Laminate

ABSTRACT

A laminate including: a rubber layer (A); and a fluororesin layer (B) laminated on the rubber layer (A), the rubber layer (A) being formed of a rubber composition for vulcanization containing: at least one unvulcanized rubber (a1) selected from acrylonitrile-butadiene rubber and its hydride, styrene-butadiene rubber, chloroprene rubber, butadiene rubber, natural rubber, isoprene rubber, ethylene-propylene-termonomer-copolymer rubber, silicone rubber, butyl rubber, and acrylic rubber; at least one compound (a2) selected from 1,8-diazabicyclo(5.4.0)undec-7-ene salts, 1,5-diazabicyclo(4.3.0)-non-5-ene salts, 1,8-diazabicyclo(5.4.0)undec-7-ene, and 1,5-diazabicyclo(4.3.0)-non-5-ene; at least one compound (a3) selected from aldehyde-amine compounds and metal hydrates; magnesium oxide (a4); and silica (a5), the fluororesin layer (B) being formed of a fluoropolymer composition containing a fluoropolymer (b1) having a copolymer unit derived from chlorotrifluoroethylene.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 14/349,859 filed Apr. 4,2014, which is a National Stage of International Application ofPCT/JP2012/075969 filed Oct. 5, 2012, and claims benefit to JapaneseApplication 2011-229997, filed Oct. 19, 2011, the contents of each ofwhich are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a laminate.

BACKGROUND ART

Growing environmental awareness has led to recent improvement in legalsystems for controlling the fuel volatilization. Especially in theautomotive industry, the fuel volatilization control is seriouslydemanded particularly in the United States. This demand has raised needsfor materials having excellent fuel-barrier properties.

Fuel delivery hoses used are laminated hoses (made of rubber except fora barrier layer) including a barrier layer formed of a fluororesin forlowering the fuel permeability. Recent strong demands for reducingenvironmental loads have raised needs for lower fuel permeability of thebarrier layer. Trials have been made for ensuring lower permeability byincreasing the thickness of the barrier layer or using perhalogenfluororesins that has the lowest permeability among fluororesins.Increase in the thickness of the barrier layer (fluororesin) howeverincreases the weight of the resulting hose, leading to a disadvantagefrom the standpoint of energy conservation. Further, such a hose haspoor bendability (flexibility), which is disadvantageous in terms ofhandleability (assembling property).

In the case where a perhalogen fluororesin is used for a barrier layer,such a barrier layer is not easily adhered to rubber of inner and outerlayers. To improve the adhesiveness, a surface treatment on the resin ora treatment of wrapping the layer with a film or tape is needed. As aresult, the procedure is complicated to cause practical disadvantagessuch as significant reduction in productivity and great increase in thecost.

As disclosed in Patent Literature 1, for example, a known means forenhancing the adhesion between a fluororesin layer and a rubber layer isuse of epoxidized rubber or a mixture of epoxidized rubber and anotherrubber for a rubber layer. Moreover, as disclosed in Patent Literature2, for direct adhesion of a rubber to a fluororesin, a thermoplasticfluororesin having a reactive functional group such as a carbonyl groupis used as a fluororesin, and a polyfunctional compound such as triallylisocyanurate is added to at least one of the thermoplastic fluororesinand a rubber layer.

As disclosed in Patent Literature 3, also known is a fuel hose having alayered structure in which a diene rubber layer and a vinylidenefluoride copolymer (THV) layer are adjacent to each other, the dienerubber layer formed of a diene rubber, such as NBR, blended with asulfur vulcanizing agent, at least one of a metal calbamate and athiazole metal salt, and magnesium oxide, together with a DBU salt andthe like.

As disclosed in Patent Literatures 4 and 5, the adhesiveness of acurable elastomeric compound to a fluoropolymer layer is known to beenhanced by using fluoropolymers including at least one monomercontaining plural hydrogen atoms or fluoropolymers essentially includingvinylidene fluoride, with a dehydrofluorinated composition mixedtherein.

Patent Literature 6 discloses a laminate including a rubber layer (A), afluororesin layer (B) on the rubber layer (A), wherein the rubber layer(A) is a layer formed of a rubber composition for vulcanization, therubber composition for vulcanization containing an unvulcanized rubber(a1), at least one compound (a2) selected from the group consisting of1,8-diazabicyclo(5.4.0)undec-7-ene, 1,5-diazabicyclo(4.3.0)-non-5-enesalts, 1,8-diazabicyclo(5.4.0)undec-7-ene, and1,5-diazabicyclo(4.3.0)-non-5-ene, magnesium oxide (a3), and silica(a4), the compound (a2) being contained in an amount of more than 1.0part by mass but not more than 5.0 parts by mass based on 100 parts bymass of the unvulcanized rubber (a1), the fluororesin layer (B) being alayer formed of a fluoropolymer composition, the fluoropolymercomposition containing a fluoropolymer (b1) having a copolymer unitderived from chlorotrifluoroethylene.

CITATION LIST Patent Literature

Patent Literature 1: JP-A H07-266501

Patent Literature 2: JP-A 2005-22403

Patent Literature 3: JP-A 2007-261079

Patent Literature 4: JP-T 2001-527104

Patent Literature 5: JP-T 2001-526921

Patent Literature 6: WO 2011/001756

SUMMARY OF INVENTION Technical Problem

The present invention aims to provide a laminate in which a rubber layerand a fluororesin layer are firmly adhered to each other without usingan adhesive or performing a surface treatment on each layer of therubber layer and the fluororesin layer.

Solution to Problem

The present invention relates to a laminate including: a rubber layer(A); and a fluororesin layer (B) laminated on the rubber layer (A), therubber layer (A) being formed of a rubber composition for vulcanization,the rubber composition for vulcanization containing: at least oneunvulcanized rubber (a1) selected from the group consisting ofacrylonitrile-butadiene rubber and its hydride, styrene-butadienerubber, chloroprene rubber, butadiene rubber, natural rubber, isoprenerubber, ethylene-propylene-termonomer-copolymer rubber, silicone rubber,butyl rubber, and acrylic rubber; at least one compound (a2) selectedfrom the group consisting of 1,8-diazabicyclo(5.4.0)undec-7-ene salts,1,5-diazabicyclo(4.3.0)-non-5-ene salts,1,8-diazabicyclo(5.4.0)undec-7-ene, and1,5-diazabicyclo(4.3.0)-non-5-ene; at least one compound (a3) selectedfrom the group consisting of dithiocarbamic acid copper salts,aldehyde-amine compounds, and metal hydrates; magnesium oxide (a4); andsilica (a5), the fluororesin layer (B) being formed of a fluoropolymercomposition, the fluoropolymer composition containing a fluoropolymer(b1) having a copolymer unit derived from chlorotrifluoroethylene.

Advantageous Effects of Invention

In lamination of a fluororesin layer and a rubber layer of the laminateof the present invention, a chemically firm adhesion is achieved duringvulcanization of the rubber without a complicated procedure. A specialtreatment for adhesion is therefore not needed, enabling easy formationat low cost. Such a laminate is produced by a common method such asextrusion, and therefore, layers can be thinner. In addition, since theamount used of a high-cost fluororesin can be limited, the resultinglaminate can be highly flexible.

DESCRIPTION OF EMBODIMENTS

The laminate of the present invention includes a rubber layer (A) and afluororesin layer (B) laminated on the rubber layer (A).

A description is given on each layer in the following.

(A) Rubber Layer

The rubber layer (A) is a layer formed of a rubber composition forvulcanization.

The rubber composition for vulcanization essentially contains anunvulcanized rubber (a1), a compound (a2), at least one compound (a3)selected from the group consisting of dithiocarbamic acid copper salts,aldehyde-amine compounds, and metal hydrates, magnesium oxide (a4), andsilica (a5). The rubber composition for vulcanization containing a metalcompound (a3) improves the adhesion strength between the layer (A) andthe layer (B), even if the amount of the compound (a2) is small.

The rubber composition for vulcanization may optionally further containat least one of a vulcanizing agent (a6) and a thiazole metal salt (a7).Especially, in the case where the rubber composition for vulcanizationcontains, in addition to the unvulcanized rubber (a1) and the compound(a2), a vulcanizing agent (a6) and the thiazole metal salt (a7), theadhesion strength between the layers (A) and (B) is greater.

A fluorine-free rubber is used as the unvulcanized rubber (a1) becauseof its excellent low-temperature resistance and favorable costperformance.

The fluorine-free rubber is at least one unvulcanized rubber selectedfrom the group consisting of acrylonitrile-butadiene rubber (NBR) andits hydride (HNBR), styrene-butadiene rubber (SBR), chloroprene rubber(CR), butadiene rubber (BR), natural rubber (NR), isoprene rubber (IR),ethylene-propylene-termonomer-copolymer rubber, silicone rubber, butylrubber, and acrylic rubber.

Exemplary termonomers of the ethylene-propylene-termonomer-copolymerrubber include monomers in a diene rubber such as natural rubber,butadiene rubber (BR), isoprene rubber, butyl rubber, and chloroprenerubber.

The unvulcanized rubber (a1) is preferably a diene rubber because it isexcellent in the heat resistance, oil resistance, weather resistance,and extrudability. More preferred is NBR or HNBR. NBR and HNBR may beused in combination.

The rubber composition for vulcanization may contain a resin forimparting the rubber layer (A) with properties different from those ofthe unvulcanized rubber (a1). Examples of the resin include PVC,chlorinated polystyrene, chlorosulfonated polystyrene ethylene,ethylene-vinyl acetate copolymers. For example, in the case where therubber composition for vulcanization contains NBR and PVC, the ozoneresistance is improved. In such a case the amount added of PVC ispreferably 10 to 70 parts by mass based on 100 parts by mass of NBR.

The compound (a2) is at least one compound selected from the groupconsisting of 1,8-diazabicyclo(5.4.0)undec-7-ene salts (DBU salts),1,5-diazabicyclo(4.3.0)-non-5-ene salts (DBN salts),1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), and1.5-diazabicyclo(4.3.0)-non-5-ene (DBN). The compound (a2) containedimproves the vulcanization properties of the rubber composition forvulcanization.

Examples of the DBU salts and DBN salts include carbonates, long chainaliphatic carboxylates, aromatic carboxylates, orthophthalates,p-toluene sulfonates, phenolates, phenolic resin salts, naphthoates,octylates, oleates, formates, and phenol novolac resin salts thereof.More preferred is at least one compound selected from the groupconsisting of 1,8-benzyl-1,8-diazabicyclo(5.4.0)-7-undecenium chloride(DBU-B), naphthoates, orthophthalates, phenolates, and formates thereof.

More specifically, the compound (a2) is at least one compound selectedfrom the group consisting of DBU, DBU-B, DBU naphtoate, DBU phenolate,DBU orthophthalate, and DBU formate.

The compound (a2) is more preferably at least one compound selected fromthe group consisting of DBU, DBU-B, DBU phenolate, DBU orthophthalate,and DBU formate. Still more preferred is at least one compound selectedfrom the group consisting of DBU-B and DBU formate, and particularlypreferred is DBU formate.

Preferably, the compound (a2) essentially contains DBU formate. Thecompound (a2) may contain DBU formate alone. Preferably, the compound(a2) contains DBU formate and DBU-B in combination, DBU formate and DBUphenolate in combination, DBU formate and DBU orothophthalate incombination, DBU formate and DBU in combination, or DBU formate and DBUnaphthoate in combination.

The amount of the compound (a2) is preferably at least 0.1 part by massbased on 100 parts by mass of the unvulcanized rubber (a1). The amountof the compound (a2) is more preferably at least 0.2 part by mass basedon 100 parts by mass of the unvulcanized rubber (a1). If the amount ofthe compound (a2) is too small, the adhesivness may be insufficient.

From the standpoint of reducing the cost of rubber without lowering thecompression set and rubber hardness after vulcanization, the amount ofthe compound (a2) is preferably at most 5.0 parts by mass and morepreferably at most 3.0 parts by mass based on 100 parts by mass of theunvulcanized rubber (a1). From the standpoint of reducing the cost, theamount is also preferably at most 1.0 part by mass.

The compound (a3) is at least one compound selected from the groupconsisting of dithiocarbamic acid copper salts, aldehyde-aminecompounds, and metal hydrates. The rubber composition for vulcanizationcontaining the compound (a3) improves the adhesion strength between thelayers (A) and (B) even if the amount added of the compound (a2) issmall as 0.2 part by mass.

Examples of the dithiocarbamic acid copper salts include dimethyldithiocarbamate copper salt (CuMDC), and diethyl dithiocarbamate coppersalt (CuEDC). Each of these may be used alone, or two or more of thesemay be used in combination. In particular, CuMDC is preferred in termsof adhesiveness and rubber properties.

Examples of the metal hydrate include a hydrate of at least one metalselected from copper, zinc, aluminum, cobalt, calcium, zirconium,nickel, and magnesium. Specific examples thereof include CuSO₄.5H₂O,ZnSO₄.H₂O, ZnSO₄.7H₂O, AlCl₃.6H₂O, n-hydrate of aluminum silicate,(Al(NO₃)₃.9H₂O), 1.5-, 2-, 4-, and 6-hydrates of CoCl₂, 2-, 4- and6-hydrates of CaCl₂, calcium silicate hydrates, calcium sulfatehydrates, 8-hydrate of zirconium oxychloride, 2-hydrate of zirconiumoxynitrate, zirconium dioxide hydrates, 6-hydrate of nickel sulfate,6-hydrate of nickel nitrate, 6-hydrate of nickel chloride, magnesiumsulfate hydrates, magnesium fluoride hydrates, 6-hydrate of magnesiumchloride, CaSO₄.5H₂O, CaSO₄.2H₂O, and 1-hydrate of calcium acetate. Themetal hydrate is preferably at least one hydrate selected from the groupconsisting of CaSO₄.2H₂O and 1-hydrate of calcium acetate, and is morepreferably 1-hydrate of calcium acetate.

The aldehyde-amine compound is preferably at least one selected from thegroup consisting of n-butyl aldehyde aniline, acetaldehyde aniline,butyl aldehyde acetaldehyde aniline, butyl aldehyde monobutylamine,butyl aldehyde butylidene aniline, formaldehyde acetaldehyde aniline,and aldehyde amine. The aldehyde-amine compound is more preferablyn-butyl aldehyde aniline.

As the compound (a3), each of the dithiocarbamic acid copper salt, metalhydrate, and aldehyde-amine compound may be used alone, or two or moreof these may be used in combination. From the standpoint of improvingthe adhesiveness, a combination use thereof is preferable.

From the standpoint of maintaining moderate vulcanization, the compound(a3) is preferably at least one compound selected from the groupconsisting of aldehyde-amine compounds and metal hydrates, and is morepreferably a metal hydrate.

In terms of quick vulcanization, the compound (a3) is preferably atleast one compound selected from the group consisting of dithiocarbamicacid copper salts and metal hydrates.

From the standpoint of improving the adhesiveness without increasing thecost, both the dithiocarbamic acid copper salt and the metal hydrate arepreferably used as the compound (a3).

The amount of the compound (a3) is preferably at least 0.1 part by mass,more preferably at least 0.3 part by mass, and still more preferably atleast 1.0 part by mass based on 100 parts by mass of the unvulcanizedrubber (a1). If the amount of the compound (a3) is too small, theadhesiveness may be insufficient.

In terms of the cost, the amount of the compound (a3) is preferably atmost 35.0 parts by mass, more preferably at most 25.0 parts by mass, andstill more preferably at most 23.0 parts by mass, based on 100 parts bymass of the unvulcanized rubber (a1).

The amount of the dithiocarbamic acid copper salt is preferably at least0.1 part by mass, more preferably at least 0.3 part by mass, and stillmore preferably at least 1.0 part by mass based on 100 parts by mass ofthe unvulcanized rubber (a1). If the amount of the dithiocarbamic acidcopper salt is too small, the adhesiveness may be insufficient.

In terms of the cost, the amount of the dithiocarbamic acid copper saltis preferably at most 5.0 parts by mass and more preferably at most 3.0parts by mass based on 100 parts by mass of the unvulcanized rubber(a1).

The amount of the aldehyde-amine compound is preferably at least 0.1part by mass, more preferably at least 0.3 part by mass, and still morepreferably at least 1.0 part by mass based on 100 parts by mass of theunvulcanized rubber (a1). If the amount of the aldehyde-amine compoundis too small, the adhesiveness may be insufficient.

In terms of the cost, the amount of the aldehyde-amine compound ispreferably at most 5.0 parts by mass and more preferably at most 3.0parts by mass based on 100 parts by mass of the unvulcanized rubber(a1).

The amount of the metal hydrate is preferably at least 1.0 part by massand more preferably at least 5.0 parts by mass based on 100 parts bymass of the unvulcanized rubber (a1). If the amount of the metal hydrateis too small, the adhesiveness may be insufficient. From the standpointof increasing the hardness, the amount is preferably at least 5.0 partsby mass.

In terms of the cost, the amount of the metal hydrate is preferably atmost 30.0 parts by mass and more preferably at most 20.0 parts by massbased on 100 parts by mass of the unvulcanized rubber (a1).

In terms of the adhesiveness and rubber properties, the amount added ofthe magnesium oxide (a4) is preferably 3 to 20 parts by mass andparticularly preferably 5 to 15 parts by mass based on 100 parts by massof the unvulcanized rubber (a1). The laminate having a specificstructure of the present invention is allowed to have excellentadhesiveness by essentially containing the magnesium oxide (a4).

As the silica (a5), basic silica and acidic silica may be used. In termsof the adhesiveness, basic silica is preferably used. Examples of thebasic silica include Carplex 1120 (DSL Japan Co., Ltd.). In terms of theadhesiveness and rubber properties, the amount added of the silica (a5)is preferably 10 to 40 parts by mass and particularly preferably 15 to25 parts by mass based on 100 parts by mass of the unvulcanized rubber(a1). The laminate having a specific structure of the present inventionis allowed to have excellent adhesiveness by essentially containing thesilica (a5).

The vulcanizing agent (a6) may be a conventionally known one selected inaccordance with the vulcanizing system of the rubber composition forvulcanization. Vulcanization of the unvulcanized rubber (a1) improvesthe mechanical strength, such as tensile strength, of a vulcanizedrubber layer to be obtained, and also provides favorable elasticity ofthe rubber layer.

The vulcanizing system employed in the present invention may be sulfurvulcanizing system, polyamine vulcanizing system, polyol vulcanizingsystem, peroxide vulcanizing system, imidazole vulcanizing system,triazine vulcanizing system, oxazole vulcanizing system, or thiazolevulcanizing system. The vulcanizing system may be appropriately selectedin accordance with, in the case where the unvulcanized rubber includes avulcanizable group (cure site), the kind of the cure site, and also inaccordance with the properties to be given to the vulcanized laminateand applications thereof.

The vulcanizing agent (a6) may be a sulfur vulcanizing agent, polyaminevulcanizing agent, polyol vulcanizing agent, peroxide vulcanizing agent,imidazole vulcanizing agent, triazine vulcanizing agent, oxazolevulcanizing agent, or thiazole vulcanizing agent in accordance with theselected vulcanizing system. Each of these may be used alone, or two ormore of these may be used in combination.

In the case where the unvulcanized rubber (a1) is a diene-typefluorine-free diene rubber (e.g., NBR, SBR, BR), the sulfur vulcanizingsystem or peroxide vulcanizing system is commonly employed. Therefore, avulcanizing agent used is preferably at least one selected from thegroup consisting of sulfur vulcanizing agents and peroxide vulcanizingagents.

Examples of the sulfur vulcanizing agents include powdered sulfur,precipitated sulfur, colloidal sulfur, surface-treated sulfur, insolublesulfur, sulfur chloride, sulfur dichloride, disulfide compounds, andpolysulfide compounds.

The amount added of the sulfur vulcanizing agent is preferably 1.0 to10.0 parts by mass based on 100 parts by mass of the unvulcanized rubber(a1). If the amount is too small, the adhesiveness may be insufficient.If the amount is too large, in contrast, the resulting rubber may be toorigid.

Preferable peroxide vulcanizing agent is an organic peroxide easilygenerating peroxy radicals in the presence of heat or a redox system.

Examples of the organic peroxide include1,1-bis(t-butylperoxy)-3,5,5-trimethyl cyclohexane,2,5-dimethylhexane-2,5-dihydroxy peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide,α,α′-bis(t-butylperoxy)-p-diisopropylbenzene,2,5-dimethyl-2,5-di(t-butylperoxy) hexane,2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, benzoylperoxide, t-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane,t-butylperoxymaleic acid, and t-butylperoxy isopropyl carbonate.Particularly preferred are dialkyl compounds.

The kind and amount added of the vulcanizing agent is commonlydetermined in accordance with the amount of active —O═O— and thedegradation temperature and the like. The amount added is commonly 0.1to 15.0 parts by mass and preferably 0.3 to 5.0 parts by mass based on100 parts by mass of the unvulcanized rubber.

The vulcanizing agent (a6) is preferably at least one selected from thegroup consisting of sulfur vulcanizing agents and peroxide vulcanizingagents, and is more preferably a sulfur vulcanizing agent. The amountadded thereof is preferably 0.5 to 5.0 parts by mass, and morepreferably 1.0 to 3.0 parts by mass based on 100 parts by mass of theunvulcanized rubber (a1).

Zinc mercaptobenzothiazole (ZnMBT) is preferably used as the thiazolemetal salt (a7).

The amount added of the thiazole metal salt (a7) is preferably 0.01 to3.0 parts by mass, more preferably 0.01 to 0.5 part by mass, and stillmore preferably 0.05 to 0.3 part by mass based on 100 parts by mass ofthe unvulcanized rubber (a1). If the amount added of the thiazole metalsalt (a7) is too small, the vulcanized rubber may have poor properties.If the amount is too large, the unvulcanized rubber may have poorproperties.

The rubber composition for vulcanization preferably contains no aminecompound because it may inhibit the vulcanizing properties and impairrubber properties.

In the present invention, additives commonly used for rubbercompositions for vulcanization may be added in accordance with purposesand needs. Examples of the additives include fillers, processing aids,plasticizers, softeners, age inhibitors, colorants, stabilizers,adhesion aids, mold release agents, conductivity imparting agents,thermal conductivity imparting agents, anti-tackifiers for surfaces,tackifiers, flexibility imparting agents, heat resistance improvers,flame retardants, UV absorbers, oil resistance improvers, blowingagents, antiscorching agents, lubricants, and epoxy resins. Further, oneor two or more common vulcanizing agents or vulcanization acceleratorsother than the above mentioned agents may be added. Here, the amount ofthese additives should be within the range that would not deterioratethe adhesiveness of the fluororesin layer (B) which is intended to beimproved in the present invention.

Examples of the fillers include: metal oxides such as calcium oxide,titanium oxide, and aluminum oxide; metal hydroxides such as magnesiumhydroxide, aluminum hydroxide, and calcium hydroxide; carbonates such asmagnesium carbonate, aluminum carbonate, calcium carbonate, and bariumcarbonate; silicates such as magnesium silicate, calcium silicate,sodium silicate, and aluminum silicate; sulfates such as aluminumsulfate, calcium sulfate, and barium sulfate; synthesized hydrotalcite;metal sulfides such as molybdenum disulfide, iron sulfide, and coppersulfide; diatom earth, asbestos, lithopone (zinc sulfide/bariumsulfide), graphite, carbon black, carbon fluoride, calcium fluoride,coke, quartz fine powder, zinc flower, talc, mica powder, wollastonite,carbon fiber, alamido fiber, various whiskers, glass fiber, organicstiffeners, and organic fillers.

Examples of the processing aids include: higher fatty acids such asstearic acid, oleic acid, palmitic acid, and lauric acid; higher fattyacid salts such as sodium stearate and zinc stearate; higher fatty acidamides such as stearic amide and oleic amide; higher fatty acid esterssuch as ethyl oleate; higher fatty amines such as stearylamine andoleylamine; petroleum waxes such as carnauba wax and ceresin wax;polyglycols such as ethylene glycol, glycerol, and diethylene glycol;aliphatic hydrocarbons such as vaseline and paraffin; silicone oils,silicone polymers, low molecular weight polyethylene, phthalate esters,phosphate esters, rosin, (halogenated) dialkyl amines, (halogenated)dialkyl sulfones, and surface active agents.

Examples of the plasticizers include phthalic acid derivatives, sebacicacid derivatives, and adipic acid derivatives. Examples of the softenersinclude lubricant oil, process oil, coal tar, castor oil, and calciumstearate. Examples of the age inhibitors include phenylenediamines,phosphates, quinolines, cresols, phenols, and dithiocarbamate metalsalts.

Examples of the epoxy resins include bisphenol A-type epoxy resins,bisphenol F-type epoxy resins, and polyfunctional epoxy resins. Amongthese, the bisphenol A-type epoxy resins are preferable as they areexcellent in chemical resistance and adhesiveness. Further, the epoxyresin represented by Formula (1):

is particularly preferable. In Formula (1), n is the average value andis preferably 0.1 to 3, more preferably 0.1 to 0.5, and still morepreferably 0.1 to 0.3. If n is less than 0.1, the adhesiveness with thefluororesin (b) tends to be lowered. If n exceeds 3, the viscosity ofthe epoxy resin itself increases and such an epoxy resin may be hardlyuniformly dispersed in the rubber composition for vulcanization.

In a case where an epoxy resin is added, the amount thereof ispreferably not less than 1 part by mass, more preferably not less than 2parts by mass, and particularly preferably 3 parts by mass, based on 100parts by mass of the unvulcanized rubber in order to further improve theadhesiveness with the fluororesin (b). From the standpoint of avoiding atoo-hard rubber layer, the amount is preferably not more than 25 partsby mass, more preferably not more than 15 parts by mass, andparticularly preferably not more than 10 parts by mass, based on 100parts by mass of the unvulcanized rubber.

The rubber composition for vulcanization is prepared by compounding theunvulcanized rubber (a1), the compound (a2), the compound (a3), themagnesium oxide (a4), and the silica (a5), and optionally with thevulcanizing agent (a6), the thiazole metal salt (a7) and otheradditives.

Compounding is performed, for example, using an open roll mill, Banburymixer, or pressurizing kneader at a temperature of not higher than 100°C.

The optimal vulcanizing time (T₉₀) of the rubber composition forvulcanization is preferably not longer than 18 minutes. The optimalvulcanizing time (T₉₀) is more preferably not longer than 15 minutes,more preferably not longer than 13 minutes, and particularly preferablynot longer than 11 minutes. The lower limit of T₉₀ is not particularlylimited, and may be not shorter than one minute, for example. The rubbercomposition for vulcanization having a composition as described abovecan shorten the vulcanization time and improve the productivity. T₉₀ isa value obtained by measuring the maximum torque value (M_(H)) and theminimum torque value (M_(L)) at 160° C. and using a formula{(M_(H))−(M_(L))}×0.9+M_(L). Here, M_(H) and M_(L) are measured inconformity with JIS K 6300-2.

Next, the fluororesin layer (B) in the laminate of the present inventionis described.

(B) Fluororesin Layer

The fluororesin layer (B) is formed of a fluoropolymer composition.

The fluoropolymer composition at least contains a fluoropolymer (b1)having a copolymer unit derived from chlorotrifluoroethylene.

The fluoropolymer (b1) is preferably a fluororesin. More specifically,the fluoropolymer (b1) is preferably at least one selected from thegroup consisting of polychlorotrifluoroethylene (PCTFE) and CTFEcopolymers.

The CTFE copolymer preferably contains a copolymer unit derived fromCTFE (CTFE unit) and a copolymer unit derived from at least one monomerselected from the group consisting of tetrafluoroethylene (TFE),hexafluoropropylene (HFP), perfluoro(alkylvinylether) (PAVE), vinylidenefluoride (VdF), vinyl fluoride, hexafluoroisobutene, a monomerrepresented by the formula:CH₂═CX¹(CF₂)_(n)X²(in the formula, X′ representing H or F, X² representing H, F, or Cl,and n representing an integer of 1 to 10), ethylene, propylene,1-butene, 2-butene, vinyl chloride, and vinylidene chloride.

The CTFE copolymer more preferably contains a CTFE unit and a copolymerunit derived from at least one monomer selected from the groupconsisting of TFE, HFP, and PAVE. Further, the CTFE copolymer still morepreferably substantially contains only these copolymer units. In termsof lower fuel permeability, it is preferable that the CTFE copolymerdoes not contain a monomer having a CH bond such as ethylene, vinylidenefluoride, and vinyl fluoride. Commonly, a perhalopolymer is hardlyadhered to rubber. In accordance with the structure of the presentinvention, however, adhesion between the fluororesin layer and therubber layer is strong even when the fluororesin layer is formed ofperhalopolymers.

The CTFE copolymer preferably has the CTFE unit in an amount of 10 to 90mol % of all the monomer units.

The CTFE copolymer particularly preferably contains a CTFE unit, a TFEunit, and a monomer (α) unit derived from a monomer (α) copolymerizablewith the above units.

The “CTFE unit” and the “TFE unit” are a part derived from CTFE(—CFCl—CF₂—) and a part derived from TFE (—CF₂—CF₂—), respectively, inthe molecular structure of the CTFE copolymer. Similarly, the “monomer(α) unit” is a part where a monomer (α) is added in the molecularstructure of the CTFE-based copolymer.

The monomer (α) is not particularly limited as long as it is a monomercopolymerizable with CTFE and TFE. Examples thereof include ethylene(Et), vinylidene fluoride (VdF), perfluoro(alkylvinylether) (PAVE)represented by CF₂═CF—ORf¹ (in the formula, Rf¹ representing a C1-C8perfluoroalkyl group), a vinyl monomer represented byCX³X⁴═CX⁵(CF₂)_(n)X⁶ (in the formula, X³, X⁴, and X⁵ being the same asor different from one another and representing a hydrogen atom orfluorine atom, X⁶ being a hydrogen atom, fluorine atom, or chlorineatom, and n representing an integer of 1 to 10), and an alkyl perfluorovinylether derivative represented by CF₂═CF—OCH₂—Rf² (in the formula,Rf² representing a C1-C5 perfluoroalkyl group). Among these, the monomer(α) is preferably at least one selected from the group consisting ofPAVE, the vinyl monomer, and the alkyl perfluoro vinylether derivative.More preferably, the monomer (α) is at least one selected from the groupconsisting of PAVE and HFP.

The alkyl perfluoro vinylether derivative preferably has Rf²representing a C1-C3 perfluoroalkyl group. More preferably, the alkylperfluoro vinylether derivative is CF₂═CF—OCH₂—CF₂CF₃.

The ratio between the CTFE unit and the TFE unit in the CTFE copolymeris CTFE unit/TFE unit=15-90/85-10 (mol %). More preferably, the ratio isCTFE unit/TFE unit=20-90/80-10 (mol %). Still more preferably, the ratiois CTFE unit/TFE unit=15-25/85-75 (mol %).

In the CTFE copolymer, preferably, the total amount of the CTFE unit andthe TFE unit is 90 to 99.9 mol % and the amount of the monomer (α) unitis 0.1 to 10 mol %. If the amount of the monomer (α) unit is less than0.1 mol %, the fluoropolymer composition tends to have poor formability,environmental stress crack resistance, and fuel crack resistance. Incontrast, if the amount of the monomer (α) unit is more than 10 mol %,the fluororesin layer (B) tends to have insufficiently low fuelpermeability, and have poor heat resistance, and mechanical properties.

The fluoropolymer (b1) is most preferably PCTFE or a CTFE-TFE-PAVEcopolymer. The CTFE-TFE-PAVE copolymer is a copolymer consistingsubstantially only of CTFE, TFE, and PAVE. PCTFE and the CTFE-TFE-PAVEcopolymer each have no hydrogen atom directly bonded to a carbon atomconstituting a main chain so that dehydrofluorination reaction does notprogress. Accordingly, a conventional method for improving theadhesiveness cannot be employed which utilizes an unsaturated bondformed in the fluoropolymer by dehydrofluorination reaction. In thepresent invention, the rubber layer (A) is a layer formed of afluororubber composition for vulcanization having a predeterminedcomposition. Therefore, adhesion between the layer (A) and the layer (B)is strong even when the fluororesin layer (B) is formed of theCTFE-TFE-PAVE copolymer.

Examples of the PAVE include perfluoro(methylvinylether) (PMVE),perfluoro(ethylvinylether) (PEVE), perfluoro(propylvinylether) (PPVE),and perfluoro(butylvinylether). Among these, the PAVE is preferably atleast one selected from the group consisting of PMVE, PEVE, and PPVE.

The amount of the PAVE unit is preferably not smaller than 0.5 mol % andnot larger than 5 mol % of all the monomer units.

The constitutional units such as a CTFE unit are quantified by ¹⁹F-NMRanalysis.

The fluoropolymer (b1) may have at least one reactive functional groupselected from the group consisting of carbonyl, hydroxy, heterocyclic,and amino groups, at a main chain terminal and/or a side chain of thepolymer.

In the present description, “carbonyl group” is a divalent carbon groupconstituted by a carbon-oxygen double bond and is exemplified by a grouprepresented by —C(═O)—. The reactive functional group such as thecarbonyl group is not particularly limited, and examples thereof includea group containing a carbonyl group as a part of the chemical structure,such as a carbonate group, a carboxylic halide group (halogenoformylgroup), a formyl group, a carboxyl group, an ester bond (—C(═O)O—), anacid anhydride bond (—C(═O)O—C(═O)—), an isocyanate group, an amidegroup, an imide group (—C(═O)—NH—C(═O)—), an urethane bond(—NH—C(═O)O—), a carbamoyl group (NH₂—C(═O)—), a carbamoyloxy group(NH₂—C(═O)O—), an ureide group (NH₂—C(═)—NH—), and an oxamoyl group(NH₂—C(═O)—C(═O)—).

In a group such as an amide group, an imide group, a urethane bond, acarbamoyl group, a carbamoyloxy group, an ureide group, and an oxamoylgroup, a hydrogen atom bonded to a nitrogen atom may be substituted by ahydrocarbon group such as an alkyl group.

Preferable examples of the reactive functional group include an amidegroup, a carbamoyl group, a hydroxy group, a carboxyl group, a carbonategroup, a carboxylic halide group, and an acid anhydride bond, becausethey can be easily introduced and the fluoropolymer (b1) is allowed tohave appropriate heat resistance and fine adhesiveness at comparativelylow temperature. Further, the reactive functional group is morepreferably an amide group, carbamoyl group, hydroxy group, carbonategroup, carboxylic halide group, or acid anhydride bond.

Especially, one containing a carbonate group and/or a carboxylic halidegroup disclosed in WO 99/45044 is particularly preferable.

The fluoropolymer (b1) may be a polymer having a reactive functionalgroup at either a main chain terminal or a side chain, or a polymerhaving a reactive functional group at both a main chain terminal and aside chain. In the case where the reactive functional group is at themain chain terminal, both terminals of the main chain may have thereactive functional groups or only one terminal may have the reactivefunctional group. In the case where the reactive functional group has anether bond, the reactive functional group may be additionally containedin the main chain.

The fluoropolymer (b1) is preferably a polymer having a reactivefunctional group at a main chain terminal, because such a polymer doesnot significantly deteriorate the mechanical properties and chemicalresistance or because it is advantageous in terms of productivity andcost.

The number of the reactive functional groups may be appropriatelydetermined in accordance with the kind, shape, purpose of adhesion,application, required adhesiveness of the rubber layer to be laminated,and a method of adhering the rubber layer to an adjacent layer.

The number of the reactive functional groups at a main chain terminaland/or a side chain terminal is preferably 3 to 800 for each 1×10⁶ ofcarbon atoms in the main chain. If the number is smaller than 3, theadhesiveness may be lowered. The lower limit is more preferably 15,still more preferably 30, and particularly preferably 120. The upperlimit thereof is preferably 200, for example, in terms of productivity.

The number of the reactive functional groups at the terminal is obtainedby the following procedure. The fluoropolymer (b1) in powder form iscompression-formed at a forming temperature that is 50° C. higher thanthe melting point of the fluoropolymer (b1) and at a forming pressure of5 MPa to give a film sheet having a thickness of 0.25 to 0.30 mm. Theinfrared absorption spectrum of the film sheet is obtained by using aninfrared spectrophotometer. The obtained infrared absorption spectrum iscompared with that of a known film so that the characteristic absorptionof the reactive functional group is determined. The number of thereactive functional groups at the terminal can be calculated based oneach difference spectrum using the following formula.The number of terminal groups (for each 1×10⁶ of carbon atoms)=(I×K)/tI: absorption of lightK: correction factort: film thickness (mm)Table 1 shows the correction factors of the terminal reactive functionalgroups as targets.

TABLE 1 Terminal group Absorption frequency (cm⁻¹) Correction factor—OC(═O)O—R 1817 1426 —COF 1884 405 —COOH 1813, (1795-1792), 1775 455—COOCH3 1795 355 —CONH₂ 3438 408 —CH₂OH 3648 2325

The correction factors shown in Table 1 are determined based on theinfrared absorption spectrum of a model compound for determining thenumber of terminal groups for each 1×10⁶ of carbon atoms in the mainchain.

A method for introducing the reactive functional group to the terminalof the main chain and/or the side chain may be a method in which amonomer (β) containing a reactive functional group is copolymerized andintroduced, a method utilizing as a polymerization initiator a compoundhaving or generating a reactive functional group, a method utilizing asa chain transfer agent a compound having or generating a reactivefunctional group, a method of introducing a reactive functional group toa fluoropolymer by a polymer reaction, and a method using these methodsin combination.

The monomer (β) containing a reactive functional group in the case wherea reactive functional group is introduced by copolymerization is notparticularly limited, as long as it is a monomer copolymerizable with amonomer to be a part of a fluoropolymer (b1) and has the reactivefunctional group. Specifically, the following monomers may beexemplified.

First example of the monomer (β) is aliphatic unsaturated carboxylicacids disclosed in WO 2005/100420. The unsaturated carboxylic acidspreferably contain at least one polymerizable carbon-carbon unsaturatedbond in the molecule and at least one carbonyl oxy group (—C(═O)—O—) inthe molecule.

The aliphatic unsaturated carboxylic acid may be an aliphaticunsaturated monocarboxylic acid or an aliphatic unsaturatedpolycarboxylic acid having two or more carboxyl groups. Examples thereofinclude C3-C6 unsaturated aliphatic monocarboxylic acids such as(meth)acrylic acids and crotonic acid.

Examples of the aliphatic unsaturated polycarboxylic acids include C3-C6unsaturated aliphatic polycarboxylic acids such as maleic acid, fumaricacid, itaconic acid, citraconic acid, measaconic acid, aconitic acid,maleic anhydride, itaconic anhydride and citraconic anhydride.

Second example of the monomer (β) is an unsaturated compound representedby the formula:CX⁷ ₂═CY¹—(Rf⁴)_(n)-Z¹(in the formula, Z¹ representing the reactive functional group; X⁷ andY¹ being the same as or different from each other and each representinga hydrogen atom or fluorine atom; Rf⁴ representing a C1-C40 alkylenegroup, C1-C40 fluorooxyalkylene group, C2-C40 fluoroalkylene grouphaving an ether bond, or C2-C40 fluorooxyalkylene group having an etherbond; n representing 0 or 1).

The amount of the reactive functional group-containing monomer (β) to beintroduced by copolymerization is preferably not smaller than 0.05 mol%, and more preferably not smaller than 0.1 mol %. If the amount is toolarge, gelation or vulcanization reaction may easily occur duringmelting by heating. Therefore, the upper limit of the amount ispreferably 5 mol % and more preferably 3 mol %.

The fluoropolymer (b1) may have a heterocyclic group or amino group at amain chain terminal or a side chain terminal of the polymer.

The heterocyclic group is a group having a hetero atom (e.g. nitrogenatom, sulfur atom, oxygen atom) in a ring of the heterocyclic moiety.The ring may be a saturated ring or unsaturated ring, and may be amonocycle or fused ring. Especially, the heterocyclic group ispreferably an oxazolyl group.

The amino group is a monovalent functional group obtained by removinghydrogen from ammonium, or a primary or secondary amine. Specifically,the amino group is represented by a formula:—NR⁴R⁵(in the formula, R⁴ and R⁵ being the same as or different from eachother and each representing a hydrogen atom or a C1-C20 monovalentorganic group). Specific examples of the amino group include —NH₂,—NH(CH₃), —N(CH₃)₂, —NH(CH₂CH₃), —N(C₂H₅)₂, and —NH(C₆H₅).

The fluoropolymer (b1) is obtainable by a conventionally knownpolymerization method such as suspension polymerization, solutionpolymerization, emulsion polymerization, and bulk polymerization. In thepolymerization, various conditions such as temperature and pressure, andthe polymerization initiator and other additives may be appropriatelydetermined in accordance with the composition or the amount of thefluoropolymer (b1).

The melting point of the fluoropolymer (b1) is not particularly limited,and is preferably 160° C. to 270° C.

The melting point of the fluoropolymer (b1) is obtained as a temperaturecorresponding to the maximum value in the melting heat curve measured ata temperature rise of 10° C./min. using a DSC device (product of SeikoInstruments Inc.). The MFR is obtained by measuring the weight (g) ofthe polymer exiting from the nozzle having a diameter of 2 mm and alength of 8 mm in a unit time (10 minutes) under a load of 5 kg atvarious temperatures with use of a melt indexer (product of TOYO SEIKISEISAKU-SHO, LTD.).

The molecular mass of the fluoropolymer (b1) is preferably within arange that allows the obtained molded products to have fine mechanicalproperties and lower fuel permeability. For example, in the case wherethe melt flow rate (MFR) is set as an index of the molecular mass, theMFR is preferably 0.5 to 100 g/10 min. at an optional temperature withina range of about 230° C. to 350° C. which is a range of the commonforming temperature of the fluoropolymers.

Examples of the polymerization initiator include: oil-soluble radicalpolymerization initiators represented by peroxy carbonates such asdiisopropyl peroxydicarbonate (IPP), di-n-propyl peroxydicarbonate(NPP); and water-soluble radical polymerization initiators such asammonium, potassium, or sodium salts of persulfuric acid, perboric acid,perchloric acid, perphosphoric acid, and percarbonate. In particular,di-n-propyl peroxydicarbonate (NPP) is preferable.

The chain transfer agent is preferably at least one selected from thegroup consisting of C1-C4 water-soluble alcohols, C1-C4 hydrocarbons orfluorocarbons, and persulfuric acid salts in terms of favorabledispersibility and uniformity in the reaction system. The chain transferagent is more preferably at least one selected from the group consistingof methane, ethane, n-butane, isobutane, methanol, n-propylalcohol,HFC-134a, HFC-32, DSP, APS and KPS. The chain transfer agent is stillmore preferably at least one selected from the group consisting ofn-propylalcohol, methanol, and isobutane.

The fluororesin layer (B) in the present invention may contain one ofthese fluoropolymers (b1) or two or more of these fluoropolymers (b1).

In the case where the laminate of the present invention is used as amaterial for the fuel field, the fluororesin layer (B) in the laminatepreferably has a fuel permeability coefficient of 10 g·mm/m²/day orless, more preferably 1.0 g·mm/m²/day or less, and still more preferably0.5 g·mm/m²/day or less.

The fuel permeability coefficient is obtained by the followingprocedure. A sheet made of a resin to be measured is placed in a cup forthe fuel permeability coefficient measurement containing a mixed solventof isooctane:toluene:ethanol=45:45:10 (volume ratio). The mass change ismeasured at 60° C. Based on the measured value, the fuel permeabilitycoefficient is calculated.

In the present invention, the fluoropolymer (b1) having a specificreactive functional group at the terminal improves the adhesion of thefluororesin layer (B) with the rubber layer (A). Accordingly, it ispossible to provide molded products (e.g. fuel tank) having excellentimpact resistance and strength.

In the case of being a perhalopolymer, the fluoropolymer (b1) has moreexcellent chemical resistance and lower fuel permeability. Theperhalopolymer is a polymer in which halogen atoms are bonded to all thecarbon atoms constituting the main chain of the polymer.

In accordance with purposes and applications, the fluororesin layer (B)may further contain various fillers such as inorganic powder, glassfibers, carbon powder, carbon fibers, and metal oxides, as far as theydo not impair the performance.

For example, with an aim of further lowering the fuel permeability, thefluororesin layer (B) may contain smectite layered clay minerals, suchas montmorillonite, beidellite, saponite, nontronite, hectorite,sauconite, and stevensite, and/or fine layered minerals having highaspect ratio such as mica.

With an aim of providing conductivity, conductive filler may be added.The conductive filler is not particularly limited, and examples thereofinclude a powdery or fibrous conductive elementary substance such asmetals and carbons, powder of conductive compounds such as zinc oxide,and powder provided with electric conductivity by a surface treatment.In the case where conductive filler is added, the fluoropolymercomposition is preferably molten and compounded and formed into a pelletin advance.

The powdery or fibrous conductive elementary substance is notparticularly limited, and examples thereof include: metal powders ofcopper and nickel; metal fibers of iron and stainless steel; carbonblack, carbon fibers, and carbon fibrils disclosed in JP-A 3-174018.

The powder provided with electric conductivity by a surface treatment isa powder obtained by conducting treatment for imparting the conductivityto the surface of a nonconductive powder such as glass beads andtitanium oxide.

The method of imparting the conductivity to the surface is notparticularly limited, and may be metal sputtering, electrolessdeposition, or the like.

Carbon black, among the conductive fillers, is favorably used because itis advantageous in terms of the economic efficiency and prevention ofstatic charge build-up.

The volume resistivity of the fluoropolymer composition containing aconductive filler is preferably 1×10° to 1×10⁹ Ω·cm. More preferably,the lower limit is 1×10² Ω·cm and the upper limit is 1×10⁸ Ω·cm.

In addition to the fillers, optional additives such as heat stabilizers,stiffeners, UV absorbers, and pigments may be added.

The laminate of the present invention is produced by lamination of therubber layer (A) and the fluororesin layer (B). In the laminate of thepresent invention, the rubber layers (A) may be laminated on both facesof the fluororesin layer (B). Or alternatively, the fluororesin layers(B) may be laminated on both faces of the rubber layer (A).

Lamination of the rubber layer (A) and the fluororesin layer (B) may becarried out by any method such as a method of laminating the rubberlayer (A) and the fluororesin layer (B), which have been separatelyformed, by pressure bonding and the like, a method of laminating therubber layer (A) and the fluororesin layer (B) by simultaneously formingthe both layers, and a method of applying the fluororesin layer (B)composition to the rubber layer (A).

In the method of laminating the rubber layer (A) and the fluororesinlayer (B), which have been separately formed, by pressure bonding andthe like, different methods may be employed to form layers for thefluoropolymer and the rubber composition for vulcanization.

Formation of the rubber layer (A) may be carried out by shaping therubber composition for vulcanization into various shapes such as a sheetand a tube by heat compression molding, transfer molding, extrusion,injection, calendering, coating, or the like.

The fluororesin layer (B) may be formed by heat compression molding,melt-extrusion molding, injection, coating (including powder coating),or the like. Forming may be carried out by using a common formingmachine for fluoropolymers such as an injection machine, a blow moldingmachine, an extrusion machine, and various coating machines. With such amachine, it is possible to produce laminates having various shapes suchas a sheet and a tube. Among these methods, melt-extrusion molding ispreferable because of its excellent productivity.

As later described, in the case where another polymer layer (C) islaminated on the fluororesin layer (B), a forming method such asmultilayer extrusion, multilayer blow molding, and multilayer injectionmay be employed to produce multilayer molded products such as multilayertubes, multilayer hoses, and multilayer tanks.

Examples of the method of laminating the rubber layer (A) and thefluororesin layer (B) by simultaneously forming the both layers includea method of forming and laminating the layers at the same time with useof the rubber composition for vulcanization for forming the rubber layer(A) and the fluoropolymer (b1) for forming the fluororesin layer (B) bya method such as multilayer compression molding, multilayer transfermolding, multilayer extrusion, multilayer injection, or doubling. Insuch a method, the rubber layer (A) as an unvulcanized formed body andthe fluororesin layer (B) are formed and laminated at the same time.Thus, a treatment for firmly adhering the rubber layer (A) and thefluororesin layer (B) is not needed and strong adhesion isadvantageously obtained in the subsequent vulcanization step.

The laminate of the present invention may be a laminate of theunvulcanized rubber layer (A) and the fluororesin layer (B).Vulcanization of such an unvulcanized laminate gives strong interlayeradhesiveness.

In other words, the present invention also relates to a vulcanizedlaminate including a vulcanized rubber layer (A1) and the fluororesinlayer (B) adhered to each other by vulcanization, which is obtained byvulcanizing the unvulcanized laminate of the present invention.

A conventionally known method and conditions for vulcanizing a rubbercomposition for vulcanization may be employed for vulcanizing theunvulcanized laminate. Exemplary methods include a method of vulcanizingan unvulcanized laminate over a long period of time and a method inwhich an unvulcanized laminate is first subjected to a heat treatment asa pretreatment for a comparatively short time (vulcanization beinginitiated during the pretreatment) and next to the vulcanizationtreatment over a long period of time. Especially, the method in which anunvulcanized laminate is first subjected to a heat treatment as apretreatment for a comparatively short time and next to thevulcanization treatment over a long period of time is preferable for thefollowing reasons. That is, adhesion between the rubber layer (A) andthe fluororesin layer (B) is easily obtained in the pretreatment.Further, since vulcanization of the rubber layer (A) starts during thepretreatment and the shape thereof is stabilized, the laminate may beheld in various ways during the subsequent vulcanization treatment.

Conditions of the vulcanization treatment are not particularly limited,and common conditions may be employed. Preferably, vulcanization isperformed at 130° C. to 260° C. for 10 minutes to 80 hours by usingsteam, pressing, an oven, an air bath, infrared rays, microwave, leadsheathing vulcanization, and the like. More preferably, vulcanization isperformed at 160° C. to 230° C. for 20 minutes to 80 hours.

Also, heating conditions during the pretreatment are not particularlylimited. Preferably, the pretreatment is performed at 100° C. to 170° C.for 30 seconds to 1 hour by using steam, pressing, an oven, an air bath,infrared rays, microwave, lead sheathing vulcanization, and the like.

In the vulcanized laminate obtained, the vulcanized rubber layer (A1)and the fluororesin layer (B) are adhered to each other byvulcanization, and the interlayer adhesion between them is strong.

The laminates of the present invention (both the unvulcanized laminateand the vulcanized laminate) each may have a two-layer structure havinga rubber layer (A and A1: hereinafter, represented by rubber layer (A))and the fluororesin layer (B), or a three-layer structure having layersof (A)-(B)-(A) or (B)-(A)-(B). Moreover, it may have a multilayerstructure having three or more layers in which a polymer layer (C) otherthan the rubber layer (A) and the fluororesin layer (B) are furtheradhered.

The polymer layer (C) may be a rubber layer (C1) other than the rubberlayer (A), a resin layer (C2) other than the fluororesin layer (B), or afiber reinforced layer. In addition, the rubber layer (A) and/or thefluororesin layer (B) may be further laminated by interposing thepolymer layer (C).

The rubber layer (C1) is made of a rubber other than the rubber used inthe rubber layer (A) that is directly adhered to the fluororesin layer(B), and the rubber may be a fluororubber or a fluorine-free rubber.Specifically, the previously mentioned examples of the unvulcanizedrubber (a1) may be used.

Here, the vulcanizing agent (a6) or other compounding agents may beadded also to the unvulcanized rubber composition for forming the rubberlayer (C1).

The resin layer (C2) may be made of a resin having excellent mechanicalstrength or a resin having low fuel/gas permeability (hereinafter, alsoreferred to as low-permeable resins). Specific examples of the resinhaving excellent mechanical strength include fluororesins (other thanthe fluororesin (B)), polyamide resins, polyolefin resins, vinylchloride resins, polyurethane resins, polyester resins, polyaramideresins, polyimide resins, polyamideimide resins, polyphenylene oxideresins, polyacetal resins, polycarbonate resins, acrylic resins, styreneresins, acrylonitrile/butadiene/styrene resins (ABS), cellulose resins,polyetheretherketone resins (PEEK), polysulfone resins, polyethersulfoneresins (PES), and polyetherimide resins. Specific examples of the resinhaving low fuel/gas permeability include resins containingethylene/vinyl alcohol copolymers, polyphenylene sulfide resins,polybutylene naphthalate resins, polybutylene terephthalate resins, andpolyphthalamide (PPA). Among these, polyamide resins are preferablebecause of their favorable formability and adhesiveness. In the casewhere a laminate is subjected to vulcanization treatment, the meltingpoint of the resin is preferably higher than the temperature of the heattreatment.

Next, the layer structure of the laminate of the present invention isdescribed.

(1) Two-Layer Structure Including Rubber Layer (A)-Fluororesin Layer (B)

This structure is a basic structure. As described above, interlayeradhesion (fluororesin layer-rubber layer) in such a structure isinsufficient. Therefore, the additional steps such as a surfacetreatment on the resin side, additional application of an adhesivebetween the layers, and fixation by wrapping with a film in a tape formhave been conventionally employed for adhesion of the rubber layer (A)and the fluororesin layer (B), and this has made the procedurecomplicated. However, according to the present invention, adhesion byvulcanization provides a chemically strong adhesion.

(2) Three-Layer Structure Including Rubber Layer-Fluororesin Layer(B)-Rubber Layer

This structure may have layers of (A)-(B)-(A) or (A)-(B)-(C1). In thecase where sealability is needed, rubber layers are preferably arrangedon both sides of the fluororesin layer (B), for example, at a joint partof a fuel pipe or the like for maintaining the sealability. The rubberlayers of the outer and inner layers may be the same as or differentfrom each other.

A fuel pipe is allowed to have enhanced chemical resistance and lowerfuel permeability by employing the (A)-(B)-(C1) structure in which therubber layer (A) is a fluorine-free rubber layer, the rubber layer (C1)is a fluororubber layer, and the fluororubber layer (C1) is an innerlayer of the pipe.

(3) Three-Layer Structure Including Resin Layer-Rubber Layer (A)-ResinLayer

This structure may have layers of (B)-(A)-(B) or (B)-(A)-(C2).

The rubber layers of the outer and inner layers may be the same as ordifferent from each other.

The resin layers arranged on the both sides stabilize the shape. Inaddition, such a structure is favorable in the case where the chemicalresistance is important. Moreover, in the case where differentmechanical properties are required on respective sides, the structuremay have layers of (B)-(A)-(C2).

(4) Three-Layer Structure Including Resin Layer (C2)-Fluororesin Layer(B)-Rubber Layer (A).

(5) Three Layer Structure Including Fluororesin Layer (B)-Rubber Layer(A)-Rubber Layer (C1)

(6) Four or More Layer Structure

Onto the three-layer structures of (2) to (5), an optional rubber layer(A) or (C1), a resin layer (B) or (C2) may be laminated in accordancewith the purpose thereof. Further, a layer of a metal foil and the likemay be laminated and an adhesive layer may be interposed between thelayers except for the rubber layer (A)-fluororesin layer (B) part.

Moreover, a polymer layer (C) may be further laminated to allow alaminate to be a lining.

Here, the thickness, shape and the like of each layer may beappropriately determined in accordance with the purpose and usagepatterns.

The laminate of the present invention, especially a vulcanized laminate,has sufficiently low fuel permeability and has excellent heatresistance, oil resistance, fuel resistance, LLC resistance, and steamresistance. Additionally, such a laminate can withstand applicationsunder severe conditions so as to be applicable in various usages.

For example, the laminate of the present invention is favorably used forseals, bellows, diaphragms, hoses, tubes, and electric cables of gasketsand non-contact and contact type packings (self-seal packing, pistonring, split ring packing, mechanical seal, oil seal, and etc.) which arerequired to have heat resistance, oil resistance, fuel resistance, LLCresistance, and steam resistance. They are used for engine body, mainengine-driving system, valve gear system, lubricating/cooling system,fuel system, and intake/exhaust system; transmission system of drivinggear system; steering system of chassis; braking system; standardelectrical parts, electrical parts for control, and accessory electricalparts for automobiles.

Specifically, the laminate of the present invention is usable for thefollowing applications.

In the basic engine, gaskets such as cylinder head gasket, cylinder headcovering gaskets, oil pan packing, and general gaskets; seals such asO-rings, packing, and timing belt covering gaskets; hoses such ascontrol hoses; engine mount rubber cushions, and sealing materials forhigh pressure valves in hydrogen storage systems.

Shaft seals such as crankshaft seal and camshaft seal in the maindriving system.

Valve stem seals of engine valves in the valve gear system.

Engine oil cooler hoses, oil return hoses, and seal gaskets of engineoil coolers; water hoses around radiators; vacuum pump oil hoses of thevacuum pumps, in the lubrication/cooling system.

Oil seals, diaphragms, and valves of the fuel pumps; fuel hoses such asfiller (neck) hoses, fuel supply hoses, fuel return hoses, and vapor(evaporator) hoses; in-tank hoses, filler seals, tank packing, in-tankfuel pump mounting of fuel tanks; tubes and connector O-rings of thefuel line tubes; injector cushion rings, injector sealer rings, injectorO-rings, pressure regulator diaphragms, and check valves of fuelinjectors; needle valves, accelerating pump pistons, flange gaskets,controlling hoses of carburetors; and valve sheets and diaphragms ofcombined air control (CAC), in the fuel system.

Intake manifold packing and exhaust manifold packing of manifolds;diaphragms, control hoses, and emission control hoses of EGR (Exhaustgas recirculation); diaphragms of BPT; anti-afterburn valve sheets of ABvalves; throttle body packing of throttles; turbo oil hoses (supply),turbo oil hoses (return), turbo air hoses, inter cooler hoses, andturbine shaft seals of turbo chargers, in the intake/exhaust system.

Bearing seals, oil seals, O-rings, packing, tor-con hoses related totransmissions system; mission oil hoses, ATF hoses, O-rings, and packingof AT in the transmission system.

Power steering oil hoses in the steering system.

Breather valves, vacuum valves, and diaphragm of master vacs, pistoncups (rubber cups) of master cylinders, oil seals, O-rings, packing,brake fluid hoses, caliper seals, and boots, in the braking system.

Insulation bodies and sheaths of electric cables (harness), and tubes ofharness exterior parts, of basic electrical components.

Covering materials for various sensor cables in the control electricalcomponents.

O-rings, packing, and cooler hoses of car air conditioners, wiper bladesof exterior equipment, as the equipment electrical components.

Suitable applications other than automotive applications include:packing, O-rings, hoses, other sealing materials, diaphragms, valves forachieving oil resistance, chemical resistance, heat resistance, steamresistance, or weather resistance in transportation system such asmarine vessels and aircrafts; similar packing, O-rings, sealingmaterials, diaphragms, valves, hoses, rolls, tubes, chemical resistantcoatings, and linings in chemical plants; similar packing, O-rings,hoses, sealing materials, belts, diaphragms, valves, rolls, and tubes infood plant equipment and food equipment (including household goods);similar packing, O-rings, hoses, sealing materials, diaphragms, valves,and tubes in nuclear plant equipment; similar packing, O-rings, hoses,sealing materials, diaphragms, valves, rolls, tubes, linings, mandrels,electric cables, flexible joints, belts, rubber plates, weather strips,roll blades in PPC copiers, in common industrial goods. For example,backup rubber materials of a PTFE diaphragm has been problematicallyworn out or torn during use because of its poor slippage. However, thelaminate of the present invention can solve such a problem and isfavorably used.

In use as rubber sealing materials for food, the conventional rubbersealing materials problematically have aromatizing properties and rubberchips may be immixed in food. However, the laminate of the presentinvention can solve such problems and is favorably used. A rubbermaterial is problematically swollen when used as a sealing material forpiping that uses a solvent for rubber sealing materials for medical andchemical application. However, use of the laminate of the presentinvention in which rubber is coated with the resin can solve such aproblem. In common industrial field, the laminate of the presentinvention is favorably used in rubber rolls, O-rings, packing, sealingmaterials, and the like, with an aim of enhancing the strength,slippage, chemical resistance, and permeability of the rubber material.Especially, the laminate of the present invention is favorably used inpacking of lithium ion batteries as it can maintain the chemicalresistance and the sealing property at the same time. Additionally, thelaminate of the present invention is favorably used in applicationsrequiring the sliding property by low friction.

Among these, the laminate of the present invention is preferably usedfor fuel pipes in terms of heat resistance and low fuel permeability. Inother words, the present invention also relates to a fuel pipe formedusing the laminate.

Fuel pipes made of the laminate of the present invention may be producedby a common method and the method is not particularly limited. The fuelpipes in the present invention include a corrugate tube.

EXAMPLES

The present invention is now described with reference to examples, butis not limited only to these examples.

Hereinafter, fluororesins used in examples and comparative examples andevaluation methods thereof are described.

(1) Composition of Polymer

The composition was measured by ¹⁹F-NMR analysis.

(2) Melting Point

The melting point was obtained as a temperature corresponding to themaximum value of the melting peaks measured by a SEIKO DSC device(product of Seiko Instruments Inc.) when the temperature was increasedat 10° C./min.

(3) MFR (Melt Flow Rate)

The MFR was obtained by measuring the weight (g) of the polymer exitingfrom the nozzle having a diameter of 2 mm and a length of 8 mm per unittime (10 minutes) under a load of 5 kg at various temperatures with useof a melt indexer (product of TOYO SEIKI SEISAKU-SHO, LTD.).

(4) Measurement of Fuel Permeability Coefficient of Monolayer

Resin pellets were each placed in a die having a diameter of 120 mm andset in a press machine heated to 300° C. The pellets were respectivelymolten and pressed at a pressure of about 2.9 MPa to give sheets havinga thickness of 0.15 mm. The sheets were each placed in a SUS 316 cup forthe fuel permeability coefficient measurement (40 mmϕ of internaldiameter, 20 mm of height) containing 18 mL of CE 10 (fuel containing amixture of isooctane:toluene=50:50 (volume ratio) blended with 10% byvolume of ethanol). The mass change was measured at 60° C. for 1000hours. Based on the time rate of the measured mass change and thesurface area and thickness of the sheet in a wetted part, the fuelpermeability coefficient (g·mm/m²/day) was calculated.

Synthesis Example 1 (Fluororesin (1))

A jacketed polymerization vessel equipped with a stirrer and having acapacity of 174 kg of water was charged with 51.5 kg of demineralizedpure water, the gaseous phase inside the vessel was sufficientlysubstituted with pure nitrogen gas, and the nitrogen gas was thenremoved by evacuation. Then, 40.6 kg of octafluorocyclobutane, 1.3 kg ofchlorotrifluoroethylene (CTFE), 4.5 kg of tetrafluoroethylene (TFE), and2.8 kg of perfluoro(propyl vinyl ether)(PPVE) were fed into the vesselunder pressure. n-Propyl alcohol (PrOH) (0.075 kg) was added as a chaintransfer agent, the temperature was adjusted to 35° C., and stirring wasstarted. Thereto was added 0.44 kg of a 50% (by mass) solution ofdi-n-propyl peroxydicarbonate (NPP) in methanol as a polymerizationinitiator to start the polymerization. During the polymerization, amonomer mixture prepared so as to have the same composition (monomerratio) as the desired copolymer composition was additionally fed tomaintain the pressure inside the vessel at 0.66 MPa. After thepolymerization, the residual gas in the vessel was discharged byevacuation, and the polymer formed was taken out, washed withdemineralized pure water, and dried to give 30.5 kg of a CTFE copolymeras a granular powder. The copolymer was then melt-kneaded on a ϕ50 mmsingle screw extruder at a cylinder temperature of 290° C. to givepellets. The CTFE copolymer obtained in the form of pellets was thenheated at 205° C. for 8 hours. Table 2 shows the properties of theresulting polymer. The number of functional groups for each 10⁶ ofcarbon atoms in the main chain was 180.

Synthesis Example 2 (Synthesis of the Fluororesin (2))

A jacketed polymerization vessel equipped with a stirrer and having acapacity of 174 kg of water was charged with 51.5 kg of demineralizedpure water, the gaseous phase inside the vessel was sufficientlysubstituted with pure nitrogen gas, and the nitrogen gas was thenremoved by evacuation. Then, 40.6 kg of octafluorocyclobutane, 2.0 kg ofchlorotrifluoroethylene (CTFE), 6.6 kg of tetrafluoroethylene (TFE), and4.2 kg of perfluoro(propyl vinyl ether) [PPVE] were fed into the vesselunder pressure. n-Propyl alcohol (PrOH) (0.098 kg) was added as a chaintransfer agent, the temperature was adjusted to 35° C., and stirring wasstarted. Thereto was added 0.13 kg of a 50% (by mass) solution ofdi-n-propyl peroxydicarbonate (NPP) in methanol as a polymerizationinitiator to start the polymerization. During the polymerization, amonomer mixture prepared so as to have the same composition (monomerratio) as the desired copolymer composition was additionally fed tomaintain the pressure inside the vessel at 0.80 MPa. After thepolymerization, the residual gas in the vessel was discharged byevacuation, and the polymer formed was taken out, washed withdemineralized pure water and dried to give 30.5 kg of a CTFE copolymeras a granular powder. The copolymer was then melt-kneaded on a ϕ50 mmsingle-screw extruder at a cylinder temperature of 320° C. to givepellets. The CTFE copolymer obtained in the form of pellets was thenheated at 190° C. for 12 hours. Table 2 shows the properties of theresulting polymer. The number of functional groups for each 10⁶ ofcarbon atoms in the main chain was 30.

Table 2 shows fluororesins used in examples and comparative examples.

TABLE 2 Fuel Thickness MFR perme- of fluoro- Melting (g/10 min.) abilityresin Fluoro- point (Measurement (g · mm/ sheet polymer (° C.)temperature) m²/day) (μm) Fluro- CTFE/TFE/ 246 29.2 0.4 120 resin PPVE(297° C.) (1) copolymer 21.3/76.3/ 2.4 (mol %) Fluoro- CTFE/TFE/ 246 3 0.4 120 resin PPVE (297° C.) (2) copolymer 21.3/76.3/ 2.4 (mol %)(Rubber Compositions A to J and a to e for Vulcanization)

Materials shown in Table 3 were separately compounded using a 8-inchopen roll mixer to give rubber compositions A to J and a to e forvulcanization in a sheet shape having a thickness of about 3 mm.Numerical values in Table 3 are each expressed in units of part by mass.

A maximum torque value (M_(H)) and a minimum torque value (M_(L)) at160° C. were measured using a curelastometer type II (model: JSRcurelastometer, product of JSR Trading Co., Ltd.) for each of the rubbercompositions A to J and a to e for vulcanization. Based on themeasurement, the induction time (T₁₀) and the optimal vulcanizing time(T₉₀) were calculated. M_(H) and M_(L) were measured in conformity withJIS K 6300-2. Table 4 shows the measurement results.

TABLE 3 Category of compounding Rubber composition for vulcanizationingredients Product name Maker A B C D E F G H Base polymer Nipol DN101ZEON CORPORATION 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Stearicacid Stearic acid 50S New Japan Chemical Co., Ltd. 1.0 1.0 1.0 1.0 1.01.0 1.0 1.0 MgO Kyowa Mag 150 Kyowa Chemical Industry Co., Ltd. 10.010.0 10.0 10.0 10.0 10.0 10.0 10.0 DBU formate SA-603 San-Apro Ltd. 1.01.0 1.0 1.0 1.0 0.5 0.5 0.5 Carbon black SEASTS Tokai Carbon Co., Ltd.50.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0 Silica Carplex 1120 DSL Japan20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 Calcium sulfate — KishidaChemical Co., Ltd. 5.0 20.0 — — — — — 20.0 dihydrate Calcium acetate —Wako Pure Chemical Industries, Ltd. — — — — — 20.0 — — monohydratePlasticizer Thiokol TP-95 Rohm and Haas 20.0 20.0 20.0 20.0 25.0 25.025.0 25.0 Sulfur Sulfur powder Hosoi Chemical Industry Co., Ltd. 1.5 1.51.5 1.5 1.5 1.5 1.5 1.5 Thiazole vulcanizing NOCCELER MSA-G OUCHI SHINKOCHEMICAL 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 agent INDUSTRIAL CO., LTD.Thiazole metal salt NOCCELER MZ OUCHI SHINKO CHEMICAL 0.2 0.2 0.2 0.20.2 0.2 0.2 0.2 (ZnMBT) INDUSTRIAL CO., LTD. Dithiocarbamic acidNOCCELER TTCu OUCHI SHINKO CHEMICAL — — 0.3 1.0 1.0 1.0 3.0 3.0 coppersalts INDUSTRIAL CO., LTD. Dithiocarbamates NOCCELER EZ OUCHI SHINKOCHEMICAL — — — — — — — — INDUSTRIAL CO., LTD. Dithiocarbamates NOCCELERPZ OUCHI SHINKO CHEMICAL — — — — — — — — INDUSTRIAL CO., LTD.Dithiocarbamates NOCCELER BZ OUCHI SHINKO CHEMICAL — — — — — — — —INDUSTRIAL CO., LTD. Amine-aldehyde NOCCELER 8 OUCHI SHINKO CHEMICAL — —— — — — — — compounds INDUSTRIAL CO., LTD. Category of compoundingRubber composition for vulcanization ingredients Product name Maker I Ja b c d e Base polymer Nipol DN101 ZEON CORPORATION 100.0 100.0 100.0100.0 100.0 100.0 100.0 Stearic acid Stearic acid 50S New Japan ChemicalCo., Ltd. 1.0 1.0 1.0 1.0 1.0 1.0 1.0 MgO Kyowa Mag 150 Kyowa ChemicalIndustry Co., Ltd. 10.0 10.0 10.0 10.0 10.0 10.0 10.0 DBU formate SA-603San-Apro Ltd. 0.5 0.2 1.0 — 0.5 0.5 0.5 Carbon black SEASTS Tokai CarbonCo., Ltd. 50.0 50.0 50.0 50.0 50.0 50.0 50.0 Silica Carplex 1120 DSLJapan 20.0 20.0 20.0 20.0 20.0 20.0 20.0 Calcium sulfate — KishidaChemical Co., Ltd. — — — 20.0 — — — dihydrate Calcium acetate — WakoPure Chemical Industries, Ltd. — — — — — — — monohydrate PlasticizerThiokol TP-95 Rohm and Haas 25.0 25.0 20.0 20.0 25.0 25.0 25.0 SulfurSulfur powder Hosoi Chemical Industry Co., Ltd. 1.5 1.5 1.5 1.5 1.5 1.51.5 Thiazole vulcanizing NOCCELER MSA-G OUCHI SHINKO CHEMICAL 1.0 1.01.0 1.0 1.0 1.0 1.0 agent INDUSTRIAL CO., LTD. Thiazole metal saltNOCCELER MZ OUCHI SHINKO CHEMICAL 0.2 0.2 0.2 0.2 0.2 0.2 0.2 (ZnMBT)INDUSTRIAL CO., LTD. Dithiocarbamic acid NOCCELER TTCu OUCHI SHINKOCHEMICAL — 3.0 — 1.0 — — — copper salts INDUSTRIAL CO., LTD.Dithiocarbamates NOCCELER EZ OUCHI SHINKO CHEMICAL — — — — 3.0 — —INDUSTRIAL CO., LTD. Dithiocarbamates NOCCELER PZ OUCHI SHINKO CHEMICAL— — — — — 3.0 — INDUSTRIAL CO., LTD. Dithiocarbamates NOCCELER BZ OUCHISHINKO CHEMICAL — — — — — — 3.0 INDUSTRIAL CO., LTD. Amine-aldehydeNOCCELER 8 OUCHI SHINKO CHEMICAL 3.0 — — — — — — compounds INDUSTRIALCO., LTD.

TABLE 4 Rubber composition for vulcanization A B C D E F G H I J a b c de M_(L) (N) 3.9 3.0 3.7 2.7 2.5 2.7 2.1 2.7 4.4 4.7 2.1 2.5 2.8 2.1 2.9M_(H) (N) 24.2 23.9 23.2 22.5 21.1 26.0 17.3 18.1 17.1 16.2 22.3 34.318.2 18.3 17.0 T₁₀ (min) 1.5 1.5 1.5 1.0 1.5 1.0 1.0 1.0 1.5 0.5 1.5 1.51.0 1.0 1.0 T₉₀ (min) 12.5 12.5 11.0 12.5 12.0 11.0 3.0 3.0 11.5 2.012.0 9.0 3.0 3.0 3.0

Examples 1 to 10 and Comparative Examples 1 to 5

A sheet (about 3 mm thick) of a rubber composition for vulcanizationshown in Table 3 and a fluororesin sheet having a thickness shown inTable 2 were stacked with a fluororesin film (10 μm thick, product ofDaikin Industries, ltd., trade name: Polyflon PTFE M731 skive film)having a width of about 10 to 15 mm interposed therebetween on one endportion. The stack was inserted into a die containing a metal spacer soas to make a sheet having a thickness of 2 mm, and was pressed at 160°C. for 45 minutes to give a sheet-shaped laminate.

The obtained laminate was cut into three sets of strip specimens (10 mmwidth×40 mm length) each with a grip that is a part where thefluororesin sheet is peeled. The adhesion strength of the specimens wasmeasured by performing a peeling test at a tensile speed of 50 mm/min.at 25° C. using an autograph (product of Shimadzu Corporation, AGS-J 5kN) in conformity with the method disclosed in DIS-K-6256 (Adhesion testof cross-linked rubber). The average value of the obtained data (N=3)was calculated and determined as the adhesion strength. Further, thedetachment was observed and evaluated based on the following criteria.Table 5 shows the results.

(Evaluation of Adhesion)

Good: Material corruption of the rubber composition for vulcanization orthe fluororesin occurred on the interface of the laminate to allow nodetachment.

Poor: Detachment comparatively easily occurred on the interface of thelaminate.

TABLE 5 Rubber Adhesion composition for Fluororesin strength Evaluationvulcanization layer (N/cm) of adhesion Example 1 A (1) 23 Good (2) 27Good Example 2 B (1) 24 Good (2) 25 Good Example 3 C (1) 22 Good (2) 28Good Example 4 D (1) 26 Good (2) 29 Good Example 5 E (1) 27 Good (2) — —Example 6 F (1) 24 Good (2) — — Example 7 G (1) 28 Good (2) 29 GoodExample 8 H (1) 26 Good (2) — — Example 9 I (1) 22 Good (2) 21 GoodExample 10 J (1) 25 Good (2) 27 Good Comparative a (1) 13 Poor Example 1(2) 13 Poor Comparative b (1)   <1.0 Poor Example 2 (2)   <1.0 PoorComparative c (1)   <1.0 Poor Example 3 (2) — — Comparative d (1)   <1.0Poor Example 4 (2) — — Comparative e (1)   <1.0 Poor Example 5 (2) — —

Example 11

The rubber composition for vulcanization and the fluororesin werecontinuously extruded using an extrusion machine. Here, the inner-layermaterial was the rubber composition A for vulcanization, themiddle-layer material was the fluororesin (1), and the outer-layermaterial was the rubber composition A for vulcanization. A DAITEPICmandrel (product of Mitsubishi Cable Industries, Ltd.) having a diameterof 24.4 mm was used as a core material passed along with the materialsthrough the forming line. The molded product obtained by extruding therubber composition A for vulcanization and the fluororesin (1) wassteam-vulcanized in a vulcanizing autoclave to give a fuel hose havingthe above three-layer structure. In addition, CE10 was enclosed in thefuel hose and the permeation coefficient was determined based on themass change at 60° C. The coefficient was 0.4 g/m²·day.

Conditions for extrusion and for steam-vulcanization are listed below.

1) Setting of extrusion machine for inner-layer NBR and outer-layer NBR

Screw temperature: 60° C.

Cylinder 1: 70° C.

Cylinder 2: 70° C.

Head: 80° C.

Thickness of molded product: 2.4 mm (both inner layer and outer layer)

2) Setting of extrusion machine for middle-layer fluororesin

Cylinder 1: 260° C.

Cylinder 2: 265° C.

Cylinder 3: 270° C.

Shell clamp: 270° C.

Neck: 270° C.

Die: 270° C.

Head: 270° C.

Thickness of molded product: 0.15 mm

3) Condition for steam vulcanization of molded product 160° C.×60minutes

INDUSTRIAL APPLICABILITY

The laminate of the present invention, especially the vulcanizedlaminate, is excellent, not only in low fuel permeability, but also inheat resistance, oil resistance, fuel resistance, LLC resistance, andsteam resistance. They are favorably used for seals, bellows,diaphragms, hoses, tubes, and electric cables of gaskets and non-contactand contact type packings (self-seal packing, piston ring, split ringpacking, mechanical seal, oil seal, and etc.) which are required to haveheat resistance, oil resistance, fuel resistance, LLC resistance, andsteam resistance. They are used for the engine body, main engine-drivingsystem, valve gear system, lubricating/cooling system, fuel system, andintake/exhaust system; transmission system of driving gear system;steering system of chassis; braking system; standard electrical parts,electrical parts for control, and accessory electrical parts forautomobiles.

The invention claimed is:
 1. A laminate comprising: a rubber layer (A);and a fluororesin layer (B) laminated on the rubber layer (A), therubber layer (A) being formed of a rubber composition for vulcanization,the rubber composition for vulcanization containing: at least oneunvulcanized rubber (a1) selected from the group consisting ofacrylonitrile-butadiene rubber and its hydride; at least one compound(a2) selected from the group consisting of1,8-diazabicyclo(5.4.0)undec-7-ene, 1,8-diazabicyclo(5.4.0)undec-7-enephenolate, and 1,8-diazabicyclo(5.4.0)undec-7-ene formate; at least onecompound (a3) selected from the group consisting of aldehyde-aminecompounds and metal hydrates, the metal hydrates being at least oneselected from the group consisting of calcium sulfate dihydrate andcalcium acetate monohydrate; magnesium oxide (a4); and silica (a5), thefluororesin layer (B) being formed of a fluoropolymer composition,wherein the fluoropolymer composition contains a fluoropolymer (b1)which has the copolymer unit derived from chlorotrifluoroethylene in anamount of 15 to 25 mol % of the total amount of the copolymer unitderived from chlorotrifluoroethylene and the copolymer unit derived fromtetrafluoroethylene, wherein the amount of the unvulcanized rubber (a1)is 100 parts by mass relative to the respective amounts of the compound(a2), the metal hydrate, the magnesium oxide (a4) and the silica (a5),the amount of the compound (a2) is 0.3 to 3.0 parts by mass based on 100parts by mass of the unvulcanized rubber (a1), the amount of the metalhydrate is 2.0 to 30.0 parts by mass based on 100 parts by mass of theunvulcanized rubber (a1), the amount of the magnesium oxide (a4) is 3 to20 parts by mass based on 100 parts by mass of the unvulcanized rubber(a1), the amount of the silica (a5) is 10 to 40 parts by mass based on100 parts by mass of the unvulcanized rubber (a1), wherein thefluoropolymer (b1) is a perhalopolymer that is a copolymer consistingessentially of chlorotrifluoroethylene, tetrafluoroethylene, andperfluoro(alkylvinylether), wherein the perfluoro(alkylvinylether) isperfluoro(propylvinylether), and wherein the total amount of thecopolymer unit derived from chlorotrifluoroethylene and the copolymerunit derived from tetrafluoroethylene is 90 to 99.9 mol % of all themonomer units.
 2. The laminate according to claim 1, wherein the rubbercomposition for vulcanization further contains at least one vulcanizingagent (a6) selected from the group consisting of sulfur vulcanizingagents and peroxide vulcanizing agents.
 3. The laminate according toclaim 1, wherein the rubber composition for vulcanization furthercontains a thiazole metal salt (a7).
 4. The laminate according to claim1, wherein the fluoropolymer (b1) is achlorotrifluoroethylene-tetrafluoroethylene-perfluoro(alkylvinylether)copolymer.
 5. The laminate according to claim 1, wherein the rubberlayer (A) is laminated on each side of the fluororesin layer (B).
 6. Thelaminate according to claim 1, wherein the fluororesin layer (B) islaminated on each side of the rubber layer (A).
 7. The laminateaccording to claim 1, further including, on the rubber layer (A) or thefluororesin layer (B), a polymer layer (C) other than the rubber layer(A) and the fluororesin layer (B).
 8. A laminate prepared by vulcanizingthe laminate according to claim 1, wherein the rubber layer (A) and thefluororesin layer (B) are adhered to each other by vulcanization.